This invention relates generally to tufting machines for forming fine gauge cut pile fabric and more particularly to improved knife blocks for mounting the knives in such machines.
In cut pile tufting machines an oscillating knife cooperates with an oscillating hook or looper to cut the loop of yarn that has been seized by the looper from a corresponding needle. It is conventional in such machines for the knife to be supported and retained in a knife block carried by an oscillating knife bar. Examples of the known knife blocks are illustrated in Card, U.S. Pat. No. 3,277,852; Cobble, et al, U.S. Pat. No. 3,386,398; Cobble, U.S. Pat. No. 3,604,379; and Bonner, U.S. Pat. No. 3,788,245. However, each of these knife blocks is limited to mounting one or two knives only.
The gauge of a pile fabric is determined by the spacing between adjacent gauge parts, i.e., the needles, loopers, and knives. Thus, the spacing between each pair of knives mounted in a knife block is the measure of a gauge of the cut pile fabric produced. In fine gauge cut pile fabric, i.e., one tenth gauge and smaller, the spacing between a point on one knife to the corresponding point on an adjacent knife is respectively 0.1 inch and smaller. As a consequence of the close spacing between adjacent knives in fine gauge cut pile machines, great difficulty has been experienced with the use of the knife blocks of the prior art. One solution to this problem is illustrated in copending U.S. patent application of Wear, Ser. No. 683,862.